Apparatus for treating metals



Patented Jan. 29, 1924.

UNITED STATES PATENT OFFICE.

REGINALD H. BULLEY, or SYRACUSE, new YORK.

APPARATUS non TREATING METALS.

Original applieation"filed April 24, 1916, Serial No. 93,070." Divided and'this application filed February 8,

1918, Serial No. 216,100. Renewed To all whomc't m (.zy 607168111.

Be it known that I, REGINALD H. BULLEY, a citizen of the United States, residing at Syracuse, in the county of Onondaga and State of New York, have invented certain new and useful Improvements in and Relating to Apparatus for Treating Metals, of which the following is a specification.

This-invention relates to-apparatus for m treatingmetals by the use of arr-electric are. More particularly it has to do with apparatus for treating, melting andre'fining metals and metallic alloys.

' One of the objects of my invention is to I overcome'the difficulties experienced in actual practicewith the use of the electric arc in existing-typeset 'elec'trio'fu'rnaces, and more'pai'ti'cu'larly those "in which the basic process of refining-iron andf 'steel iscar: ried out. With" certain of the {electric m'etal refining furnaces: of'the electricarc type, which" arenow in" use, it "h"as"beeif foun'd adyisable to introduce into the ffurgiace' the nitali ina njoltenfeoiiditionyin -view of the fact that the relationship" of theatre ele'c trodes and constructibn fof'ZtheTurnace' gen: efallj 0' "not ""u'i'to len'd 'ftliemselves to the eflicientF end-economic melting of the metal from its solid state. For example, rm with the". Heroult Ty e or; electrie arc =furmace, it lias' beei1 'fofi'r'id' advisable, in many insth noes, in (widen 'to' operate it most" ep c nomically on basic steelproc'essito introduce metal i'rithe' molten "state? into'jthe furnace :15 and "their subject it 'to the infliienbe'sfjof "an electric met -a comparatively lowvoltage. This'voltage substantially limits tl'fe length ofthe' are, and mm-rem; of relatively high aiiiperage lisf initially required properly to 4 refine tliilbatlf irg the fii'rnace: "After-' the metal iii the H ra-11 fur ace-is treated with a "current" of high amperage and relatively low voltagedofithe retjuired; riod bf time, then -the value of clfr'fei it'- owing" is ma terially reduced, the voltage remaining sub stantially the same as it was at; the begin-f iiin of the process? This type of 'furnade' has een found to be relatively slow'in 0peration and uneconomical in current. consumption unless the metal isintroduced into it in athe n'folteir state, 515 above. stated; Heretofore, in order overcome some of the "objections to Heroult type set electric'arc furnace,- itfhas'lbeen' suggested to Marches 1922. Serial No. 545,570.

start melting the metal from its solid state under the influence of an electric are which was relatively longer and of higher voltage than that 'used by Heroult, and further that after the metal had been subjectedto the influence of theirelatively longer arcof relatively higher volta e for-a given time, the kilowatt load of t e work circuit including the electric arc should be reduced. With this latter type of furnace inactual practice it has been found that the melting capacity is materially increased over that of the Heroult type, but other difiiculties have been encountered with it, not present For example, with a relatively longerare of comparativelyhigh voltage, undesirable heatin and melting of the cover or top and" lining: of the side walls of the furnace has been experienced, and when 'the kilowatt load was dropped, the refiningaction' of the fum'a'ce was not satisfactory and particularly was this true in the Heroult type.

with various metallic alloys offironfand V steel."

"Withmy improved apparatus the objection to slowness and expense of melting encountered with -''the Heroult process "isovercome, the objection heretofore incident; to the systems of electric furn'ace operation in' which re lationis eifectedmerely 'by reducing an gincreasing'the length of the arc',"or varying the kilowatt load of the work circuit,"'either or both, areals'o'over cam and in addition thereto my invention provides for more "eflicientand economical refining-than results from the use of any offlthe-earlier' types of electric arc furnace for metal melting and refining pu?)os'e's and control apparatus of 'which am aware-f" '3 i 'furthenobject ofm 'invention'is to pifovideyapparatu'sjwith w ich it is possible readily to make the various steps essential to the proper treating, melting and refining of; metals by the use of an'electric are, in a simple, eificient and economical manner, it being possible for one skilled in theart to accomplish the necessary" electriccircuit regulation promptlyat will. and substantially automatic regulation likewise being possible. i For'the' purpose of settin' forth one emhddiinenflof m invention have selected herein to illdst ate and describe a construe lion of apparatus and system of correlated elements b means of. which it may he practiced.

This ap plication i 1916.

The drawing illustrates diagrammatically apparatus embodying my invention.

1 indicatesanelectric furnace ofany desired construction. It is shown as having a shell 2, of insulating material, and top or roof 3. The insulating lining and top 3 may be of any desired compositioncapable of meeting the chemical, temperature and structural requirements of a furnace oi this character. The electrodes within the furnace may be of any desired construction, number and disposition; 4-- is an electric terminal or conductor which extends up through the bottom of the furnace and makes electric contact with the metal to be treated therein, which metal constitutes, in this example, the lower electrode, the upper one 5; of which extends througlrtlie top of thei-fiurnace and-is adustable up and down relative to thelower electrode and the bottom oi the furnace in anywell known manner, asib y meansofiarack'and pin-ion mech. anism. 1 pjre'fer at the present time to make theelectrode 5- oi amorphous carbon oragira hite, thoughiany suitable composition 0 material-,willsufiiee; When the metal-fin introduced intothe furnace and contactswith the'termiinal-, the metal and the terminal 4 may be considered together asconstituting-the lower. electrode, if desiredi.;;" m 6 represents di rammatical-ly a step. downtransfocmerthe primary? winding 6- of which is connected.- in alwell known-man nor with asuitable senrceoielectricenergy, not shown.- This transformer maybe provided with ny desiredcnumber-of secondarywindingsifiy For the purposes-of illns tration I; have. shown four such secondar windings. Each of these secondary wind ings may be of any dcsired characteristic so longas any combination. of them will prodncein, the total-secondary circuit the full kilowatt. capacity of theprimary winding 6'. that is when said windiiws are connected oither'in series series para llel orra-rallel.

7 Represents diagrammatically a! 'ilowatt re%ulator of. any: preferred construction suitaby-connected, with operating mechanism 8 for tl1e upper electrode 5, which operating mechamsm; may be an electric IlIlOtQBS, suitably: geared, tothe rack and pinion mechanisIa;5',as,byz chain reduction gearing 8.

indicated in dotted lines-the operation of? the-kilowattregulator -7- being; such that lication is a division of my aperial No. 93,070, filed April 24,

- when the kilowatts in the circuit exceed: the

predetermined valuation which theregulaton isadgustedl, the regulator will operate io. connectthe motor incircuitfand; raise the electrode 5 the required distance to living the kilowatt load in the circuit back to the predetermined value, whereas when the kilowatt load in the circuit is less than the )rcdctermined value, the regulator will operate to actuate the motor so as to lower the-electrode :luntil the kilowatt load in the circuit has the predetermined value. 7' 1s a series or current transformer, thefunction of which is to supply current to the solenoid 7 which consists of a winding 7* connected in series with the current transformer 7 and a; winding"? connected across the line to the electrodes in such a manner that the current flowing in this wi-ndin will be proportional which the line to the electrodes is supplied! Thecoilsi'l' and17arc so wound as to supplement eaclt other, that is to say, that an increase of voltage across the-line produces an increase of current flowing in: 7 in the to the voltage wit same direction that an. increase at current in the line will' 'roduce an increase in the secondar transi l irmer 7' and winding 7".

1-0an 1 1 are electro-m'agnetic switches, the circuits of which are subject to the control of the master solenoid 7, the switch 10 serving to close the motor circuit so as to cause the motor armatureto rotate in. one direction, whereas the switch' 11 is adapted to close thecircuit so as tocausethearma- I tureto rotate in the opposite direction \Vhen the magnetic switch 10 is ener ed, the direction'of flow oi current throng r the field-eoilof the motor is indicated. by full line. arrows, whereas when switch 1L isenengized-to. close the motor cu cuit, the direction-of flow-oi current through the motonfield is indicated by dotted arrows, r 1 -'Ehe' control of the voltage oi the total secondary circuit, incl-ixdingthe. circuit .oetwcem'the electrodes, in the furnace, as providedfor bythe transformer 6, may not under certain conditions of. the. iurnace; and characteristics. of, themetal, being, treated, be suzflicientlyflexihlerfor obtaining theresults desired and I: have therefore provided for a further regulation of the kilowatt load of the circuit which. may. be efioctedtsdesired dependent. upon thewconditions of the metali beings treated-and 'the refining, results sought. With this. object -in: view L have provided arvariahle resistance 9 oi any de-* sired construction vfor the kilowatt regulator-7. This regulating resistance '9 serves toregulate the current flowing to the coil 7" ofthe solenoid T by shunting oil? a portion thereof as determined by the amount of re sistance introduced-1 in the shunt circuit. Since the! current given by: the seriestnansformer is always pro. rtionahtothe amonnt on current flowing t rough, the :tunnaotgeif it becomes necessary toadjust the amount at currentpassing through. the fiurnace,

'- the purpose of accomplishin under 1) varying the resistance 9 and thereby clianging the amount of current which flows through the solenoid for a given amount of current in the line. The operative may within limits regulate the kilowatt load of the circuit b cutting in or out resistance in circuit wit the kilowatt regulator as desired. While I have for the purpose of illustrationshown a yariable' resistance for this regulation,-.it will be understood tit may be accomplished within desiredlimits in any well known manner, as for example, Joy-any sort of mechanical adjustment of parts of the kilowatt regulator itself;

Inoperation, themetal or metallic alloy to be treated may be introduced into the hearth of the f urnace l in-any ,well known manner andin any desired condition. As previously stated, my inventionfls peculiarly adapted for efiiciently, -meltingl the metal r mthe solid s a u i sd ireds-t e me may be introduced into the hearth in the molten state.- The 'desired -character*and quantitytof slagjor. slag forming materials may be introduced intorthe furnace' at this timeor. later during the operationas desired. The coils of the secondary ei i'eiiit' 'preferably arerfirst lsuitably connected inseries.

Assumingthat thekilowatt capacity of the source of,s'upply .is 800 kilowattsaridthat each ofzthe secondary w iindings-is wound for 'fifty volts and has a capacity of 200-kilo watts, at the beginning of the process these secondary coils arefconnected in series by any well ,lmownconnecting. devices, not shown) ,so that the voltage of, the secon ary circuit will be 200 volts and the kilowatt loadBQO-kilowatts. Inorderto start the are between the lower end of the electrode 5 and the metal on the hearth, it maybe necessary initial! to depress the electrode 5 until the arc is established,whereupon-the electrode 5 is raised until the maximum kilowatt load of the circuit is established or substantially so, at which time [the'kilowatt regulator 7 may be connected into the circult to assist in substantially maintainin fairly constant the maximum kilowatt load on the circuit. At this time the length of the are between the bottom of the electrode 5 and the top of the material in the furnace beingtreate may be considered to befabout medium. i

proeeeding with the voltage at 2300 volts and the kilowatt load substantially 800 kilowatts for the period 'oftimer'equired to get the material being treated in the" desired condition, as determined by the condition of the furnace and nature of the metal being treated, I next lower the yoltage' of the working circuit say to'lOO volts, maintaining, however, the kilowatt load of the cirgiven conditions, it is most easily done cuit substantially the same as before, namely 800 kilowatts. With the apparatus llustrated in the drawings, this may -be accomplished by connecting any pair of themeondary windings 6 1n series and that part in parallel with any other pair of the secondary windings, similarly connected, which connections may be made electrically in any well known manner (not shown). At this time the kilowatt regulator 7'fmay require adjustment to accommodate it to the 'new voltage condition of the circuit in order that it may maintain the kilowatt load of the circuit substantially the same as it was duringthe first step.- And at this time, furthermore, the electrode 5 may have to. be lowered relative to the bath of molten metal so that-the expenditure of energy of the secondary circuit in the jfurnaee and between the electrode and bath will be such? as -to radiate more heat to the bath than wasi'the case when the arc was longer, -,the. yq'ltage higher, gandgthe current flowing in; the cir-. cult ofless amper ITheishorter the are, the fartherfit 1s riifia tiyely from the top of thaifurnace, and the 2 less destructive is its (effect ;upon ,theitop, the mass ,of the electrode itself cutting 01f the radiation of the heat from the arc to the top more effectively asthe arc is :shortenedin length, i The action of therelatively lower voltage and-shorter, are on themetal of the ba-th is continued until, the refining has been. carried onto! the desired. point as determinedjb the character and nature of the material lieing treated and the results desired; durin'i the course "of this refininit maybe lfoun adyisable to vary the'ln owatt load .of the .cir-. cuit within limits; and this maybe accomplished by the operative operatingtheresist: shoe 9 for effecting the action of thc kilowatt regulator 7. .As much as sixty .per cent regulation in this particular may be found necessary.- o. It may be found advisable in certain'instances to still further reduce the voltage, say for example to fifty volts without materially changing the kilowatt load of the workcircuit. This may be accomplished by connecting four of the secondary windings 6. in parallel in the work circuit and the adjustment 'of the electrode 5 and of the kilowatt regulator ,7 to establish the requisite arc'on the on'e hand andthe adjustment of the kilowatt regulator 7 oh the other subomaintain the constant kilowatt stantially o d' s d-p,

{Under certain circumstances, it may be advisable to introduce into the work'circuit a reactance, the function of which will be to have a smoothing out or ballasting action in the work circuit. This may readily be accomplished as by connecting in thei wofrk cllQ lllt a ieactance of any well known con- "sti'uctidii indicateddiagrammatically at 12 ,cuit across sar relatively in the drawings. This reactauce 12 may be provided with regulati'rigmeans 12 of. any well known construction, also shown diagrammatically, for varyingits capacity as desired. Tl'iesame results, of course. could be obtained by connecting inthe work circuit a suitable resistance, butthe energy. losses due thereto would be objectionable and disadvantageous as compared with those incident to the use of the reactancejust referred'to.

To-those skilled in the art 0% making apparatus of th class described, many rnodi ficati'ons of and widely differin embodiments and abplplicatioiis' of my intention will suggest 'euiseli s', without departing firou'i the spirit a'nd' scope thereof. d'isclosures anddescriptions are purely i lustrat'r'iie'- 'aiid are-1 not: intended to" be in any sense limiting.

What I clituii is:

1:; Im apparatus for treating metal by'the use offan emu-mare, the combinatiexiofa pair of relati'relY tdtlie. otliefqii'e, andmeafis' for delivering to said electrodes when positioned for-a relatively loii'garea vn' kins-m1 load, andtlien -suh'staixitially e sainel zil'owan.- l'oad '\'1i'th voltage and: in creased amperage'w electrodes are positioned for a; shorter arc. b

2. In ap aratus for treatin'gmtal by the use of air-electric are, the ebrnhination of a pair feledtrodes, and means .for adjusting one ofsaid electrodes relative to the other and maintaining the kilowatt loadof the cirelectrodes bstantiallv constant at different adjustments. of salt electrodes with decreased voltages and increased amperages as the length of the arc is decrease 3. In apparatus for treating metal by the use of an electric arc, the combination of a pair of electrodes, means for adjusting one of said electrodes relative to the other, and means f r maintaining the kilowatt load in the electrode circuit substantially constant at different adjustments of said electrodes with decreased voltages and increased amperage as the length of the are is decreased.

4. n apparatus for treating metal by the use of an electric arc, the combination ofa air of electrodes, one f which is movable to the other one, means for deliverinw to said electrodes when positioned for kilowatt load, same kilowatt load when are positioned for a shorter are, and means the kilowatt load within relatively narrow limits.

5. In apparatus for treating metal by the use of an electric arc, the combination of a. pair of electrodes, one of which is movable eleetradesen ef which i's' pr'os'alile fo r varying relatively to the other one, mea-ns for delivraring said electrodes when pfis'jfiened for a re ativel} long are a given kilowatt load, and then substantially the. same kilowatt load when the electrodes a'repositioned for a shorter are. and a reactancc in said electrode circuit.

6. In apparatus for treating meta-Hi1 the use of an electric arc, the combination ofa pluralityof relatively movable electrodes, a transformer in circuit with said electrodes and provided with a series ofsecondary windings, and means for connectingFsaid secondary windings to maintain the kiloh att load of the electrode circuit substantially constantfor different adjustments it-"said electrodes and varying 'voltagestlierel)ebetween.

Ti. In apparatus for} r'eafiiig metal by the use of an electric arc,the combination ofa plurality of relativelj'jmoyiible electrodes, a transformer" in circuit with said electiGdQ's and" provided with a series, of secondaiy windings, and means forjjcbnn'e'ctifi" said winding's in s'erie's' seri's parallel'an parallel', re'spectifiely, for ma maining the K'. V. A- load oaths elecaade'ircuii substant'i'ally constant for difieiiit' currents and lengths of are.

8; In the manufacture of aiijarc filrliaiie,.tlle co bination with for the amount. of current through the metal hath while maintaining substantially the K. W. load in the electridcir cuitl f D 9. In' the. manufacture ofmetals .irf an arc type electric .furnace, the combination with are electrodes, of electricmagnetically controlled means for varying the ainoirn t of current through the metal bat-h whileniaintai'ning substantiall the same K. W. load in the electric circuit.

l0. I'n the manufacture of metals in an arc type electric furnace, lhc con hinatiou with are electrodes. of a kiln-watt regulator for varying the amount of current through the metal bath while maintaining substantially the same kilo-watt load in thcplectric circuit.

11. In apparatus for treating metal by the use of an arc type electric furnace, the combination with a pair of electrodes; one of which is movable relatiale all other. o means for varying the v6ltage, 'ar id;means for automatically varying the relatit'ie,,posi. tion of theelectrodes to keep the IC. load substantially constant across. the electrodes for each change of voltage.

In testimony, whereof I alli'x. my signature, in, the pre. cc of two witnesses.

REGINALD H. BULLEY.

Witnesses: v

H. M,.Bunwr,

-. Cannes S. Esranuooril 

